A clinical trial in women with moderate cervical dysplasia is proposed to determine the efficacy of oral supplementation of beta-carotene (BC) in increasing the regression rate of cervical dysplasia. The secondary aim is to monitor levels of antioxidants, including vitamins C and E, in plasma as well as in target tissue and the positivity of human papillomavirus (HPV) infection throughout the study in order to determine if they are biological markers associated with histopathologic changes of the cervix. One hundred and thirty-eight women with moderate cervical dysplasia diagnosed by colposcopically directed biopsy will be recruited from the Bronx Municipal Hospital. They will be randomized, in a double-masked fashion, into either the treatment group receiving 18 mg of BC a day or the lactose placebo group. Subjects will be followed up by colposcopy at 3-month intervals. The outcome, regression from moderate to mild dysplasia or to normal, will be determined by biopsy at the 9th month. Women with endpoint regression will be followed up for another 6 months for recurrence. Blood and cervico-vaginal lavage samples will be obtained at baseline and at each follow-up visit. Levels of BC, ascorbic acid, and alpha- tocopherol will be measured in plasma and in cervico-vaginal cells. HPV infection will be determined from the lavage sample by Southern blot. Subject's dietary pattern and exposure to risk factors of cervical dysplasia will be monitored via questionnaires. Regression and recurrence rates will be compared between treatment groups in the whole population as well as in strata defined by HPV positivity or by different levels of vitamins C and E using chi-square and logistic regression. Cervical cancer is the second cause of death from cancer in women. This study will assess the efficacy of dietary supplementation with BC in additionally evaluate the effects of HPV and other antioxidants on preneoplastic lesions.